JP3462272B2 - Array electrode substrate inspection equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the electrical characteristics of an array electrode substrate, which is used for inspecting electrodes such as LCD panels (liquid crystal display panels).

[0002]

2. Description of the Related Art There is known a device for measuring an electric potential of an electrode on a panel by using an electro-optical effect (EO effect). In this device, an electro-optic probe (EO probe) made of a material having an electro-optic effect is brought close to an electrode to cause a change in the refractive index according to an electric field, and this is irradiated with a laser beam light to reflect reflected light. This is a device for reading the potential of the electrode on the panel by reading the change in the polarization state of.

As such a conventional technique, for example, JP-A-64-9370 and 64-18071 are disclosed.
In addition to the publications (first literature), 64-18072 publication, 64-18073 publication, and JP-A-3-244141 (second publication), the following publication "IEICE TRANS. ELECTRON.,"
VOL. E76-C, NO. 1 JANUARY 19
93, PP64-67 "(third document)" IEEE JOURNAL OF QUANTUM "
ELECTRONICS, VOL. QE-22,
NO. 1, JANUARY 1986, PP69-7
8, PP 79-93 ”and the like are known.

Among them, as one that can be used for measuring the potentials of a large number of electrodes on an array electrode substrate of a liquid crystal display panel or the like, in the above-mentioned first document, one linearly polarized light using a large electro-optic probe is used. The measurement laser beam light is scanned to enable two-dimensional potential distribution measurement. Further, in the above-mentioned second and third documents, parallel light having a certain spread is incident on the electro-optical modulator, not the light beam that is narrowed down, and the potential distribution of a region including a large number of electrodes is measured at one time. I can do it.

[0005]

However, the potentials of a large number of electrodes arranged on the array electrode substrate can be accurately and quickly detected.
Moreover, it is difficult to measure only the electrodes. For example, in the above-mentioned first document, since one measurement laser beam is sequentially scanned, it takes a long time to finish the measurement of many electrodes. Also, since it is difficult to increase the size of one electro-optic crystal (make it long),
The measurement range for one scan cannot be very wide. According to the above-mentioned second and third documents, a large number of electrodes can be simultaneously measured at one time, but a portion other than the electrodes will also be measured.

Therefore, for inspection of an array electrode substrate in which an extremely large number of electrodes are arranged, such as a liquid crystal display panel, it has been desired to provide a new inspection device for the array electrode substrate.

Here, a liquid crystal display panel, which is a type of array electrode substrate, is constructed as shown in FIG. 16 or FIG. FIG. 16 shows a liquid crystal display panel for monochrome display. On the upper surface of the glass panel, substantially square pixel electrodes (unit electrodes) are regularly formed in the left-right direction to form an array electrode, and a plurality of array electrodes are arranged in a vertical direction orthogonal to the array direction. As a result, the unit electrodes are two-dimensionally arranged in a matrix on the panel. A data line is provided in the array direction between the unit electrodes and a scanning line is provided in a direction orthogonal to the data line, and a voltage is applied to the unit electrode, which is a pixel electrode, at the intersection of these lines.
As a switch to turn off, thin film transistor (TFT)
Are formed. A liquid crystal display panel as a display device is formed by disposing a liquid crystal material on this panel and providing a common electrode (both not shown) on the opposite surface.

A liquid crystal display panel for color display is constructed, for example, as shown in FIG. Pixel electrodes are R (red), G
Although it is provided corresponding to the three colors of (green) and B (blue), and R, G, and B color filters (not shown) are arranged, it is different from the black and white display, but is otherwise the same. Also in the case of this color display, the unit electrodes are arranged like strips in the array direction to form an array electrode, and a large number of the unit electrodes are arranged in the direction orthogonal to the array direction, whereby the unit electrodes are arranged in a matrix.

In such a liquid crystal display panel, for example, 6
With 40 dots x 480 dots x 3 color VGA,
The unit electrode, which is a pixel electrode, is 921,01 per panel.
It has 600 pixels.

The present invention provides an inspection of an array electrode substrate in which such a large number of unit electrodes are regularly and two-dimensionally arranged.
It is an object of the present invention to provide an inspection apparatus for an array electrode substrate that can be executed with high accuracy in a short time.

[0011]

According to the present invention, a plurality of array electrodes in which a plurality of unit electrodes whose potentials are to be measured are arranged in one direction are arranged at a predetermined arrangement interval in a direction orthogonal to the array direction. Thus, in an inspection device for inspecting an array electrode substrate in which unit electrodes are two-dimensionally arranged, a probe array in which a plurality of electro-optical probes each having a length in the array direction including a plurality of unit electrodes are arranged at a predetermined pitch. A probe assembly in which each electro-optical probe of one probe array and each electro-optical probe of the other probe array are arranged in a zigzag pattern, and a plurality of electric wires of the probe assembly. Array of probe light source that outputs multiple measurement beam lights corresponding to each optical probe, and array of multiple measurement beam lights from the probe light source Deflecting means for repeatedly deflecting in the direction or in the oblique direction, an optical system for injecting the plurality of measurement beam lights deflected by the deflecting means into each of the plurality of electro-optical probes, and an incidence for the plurality of electro-optical probes. An optical path converting means for converting the optical paths of a plurality of reflected return light beams of a plurality of measurement beam lights, and a light detection means for detecting a plurality of reflected return light beams whose optical paths are converted by the optical path conversion means for each of a plurality of electro-optical probes. The probe assembly and the array electrode substrate are moved in a direction orthogonal to the array direction by a distance corresponding to the arraying of the array electrodes in synchronization with a repeating cycle of deflection of the measurement beam light by the deflecting means. To do.

[0012]

According to the structure of the present invention, since the plurality of electro-optical probes are arranged in a staggered manner in the probe assembly,
Multiple small electro-optic probes (eg 8, 16
(20 pieces, 40 pieces, etc.) is equivalent to constructing a long electro-optic probe, so that the potentials of many unit electrodes can be simultaneously measured. That is, since the measurement beam light is incident on each electro-optical probe and each reflected return light is detected by the photo-detecting means, the potentials of the unit electrodes corresponding to the number of electro-optical probes can be simultaneously measured. Then, since the deflection of the measurement beam light in the array direction or this oblique direction is synchronized with the relative movement of the array electrode and the probe assembly in the direction orthogonal to the array direction, when the measurement of the array electrode of a certain line is completed,
Measurement of the next line of array electrodes can begin, resulting in continuous potential measurement.

Further, the probe light source may have a plurality of semiconductor lasers which respectively output a plurality of measurement beam lights, and the light detecting means may have a plurality of optical sensors which respectively detect a plurality of reflected return lights. By doing so, it is possible to realize an extremely practical array electrode substrate inspection device with a simple structure of the light source and the light detection means.

The moving means may have a stage on which the array electrode substrate is placed and which moves the array electrode substrate in a direction orthogonal to the array direction. By doing so, the relative movement of the array electrode substrate and the probe assembly can be realized simply by driving the stage while keeping the apparatus main body stationary.

Further, the measurement beam light is deflected by the deflecting means and is incident on the electro-optical probe in the region corresponding to one unit electrode, and the unit electrode is set to a potential to be measured a plurality of times within a time period in which the pulse is applied. You may make it further have a pulse drive source which supplies a drive signal to an array electrode substrate. With this configuration, the potential of the unit electrode can be accurately measured while the array electrode substrate is driven while the measurement beam light is continuous light.

Further, the electro-optical probe is made of a material which causes a photoconductive effect by light having a wavelength shorter than that of the measuring beam light, and a direct current drive source for supplying a direct current drive signal for setting the unit electrode to a potential to be measured to the array substrate. , A light source for irradiating a plurality of electro-optical probes with the above-mentioned short-wavelength light, and within a time during which the measurement beam light is incident on the electro-optical probe in the region corresponding to one unit electrode by being deflected by the deflection means. Further, chopping means for making the irradiation of the short-wavelength light on the electro-optical probe blink may be further provided. By doing so, the potential of the unit electrode can be measured while the array electrode substrate is driven by direct current. That is, when the chopping light is irradiated, the change in the refractive index of the electro-optic probe due to the electro-optic effect is canceled by the photoconductive effect, which can be equivalent to pulse-driving the array electrode substrate.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a diagram for explaining the basic construction of an array electrode substrate inspection apparatus according to the first embodiment, and FIG. 2 is a diagram showing the relationship between the array electrode substrate and the probe assembly in this embodiment. is there. In this embodiment, one inspection device is constructed by combining a total of 20 inspection units. In the example of FIG. 1, components other than a laser light source, an electro-optical probe, and an optical sensor, which are an example of a probe light source, are common to each inspection unit, but are independent for each inspection unit. May be.

As shown in FIG. 1, a color display LC is formed on the upper surface of the XY stage 1 as an example of an array electrode substrate.
The D panel 2 is placed and movable in the X and Y directions. The output terminal of the pulse drive signal source 31 is connected to the electrode terminal (scanning signal input terminal) of the LCD panel 2, and the TFT switch is turned on in synchronization with the application of the pulse signal to the scanning line of the LCD panel 2. As a result, the pulse signal voltage is applied to the unit electrode 21 (see FIG. 2) which is the pixel electrode via the data line to which the DC bias is applied.

A probe assembly 4 is arranged above the XY stage 1 at a position close to the upper surface of the LCD panel 2. As shown in FIG. 2, the probe assembly 4 includes a total of 20 probes 41 _{1 to} 41 made of electro-optical materials.
It is equipped with ₂₀ arranged in a staggered pattern, and the probes 4 in the upper row.
1 _{1 to} 41 ₁₀ and the lower row probes 41 _{11 to} 41 ₂₀ have a positional relationship in which both ends thereof are slightly overlapped with each other, and the distance between the centers of the upper row probe array and the lower row probe array is the LCD to be inspected. It is the same as the array pitch in the vertical direction (Y direction) of the array electrodes (the array of the unit electrodes 21) on the panel 2 or an integral multiple thereof.

The probe unit, that is, the probe assembly 4, has 20 probes 41 on a single support plate 40.
By fixing the _{1-41 20} physically they are integrated. Then, as indicated by an arrow in FIG. 2, the probe assembly 4 scans the electrode area (display area) 20 on the upper surface of the LCD panel 2 from the upper left end to the lower right end. This scanning is performed by a combination of the X-direction drive and the Y-direction drive of the XY stage 1.

A condenser lens 5, a 1/8 wavelength plate 6, a polarization beam splitter 7, a deflector 8 and a laser light source 9 are arranged above the probe assembly 4 in this order from the XY stage 1 side. . The laser light source 9 has a probe assembly 4 total twenty semiconductor lasers 91 ₁ to 91 ₂₀ in response to, twenty measurement laser beam light therefrom output by the deflector 8 which is externally controlled The laser light is deflected in the X direction, transmitted through the polarization beam splitter 7, becomes linearly polarized laser light, and enters the ⅛ wavelength plate 6. After the optical bias is given by the ⅛ wavelength plate to make it elliptically polarized, the 20 measurement laser beam lights condensed by the condenser lens 5 are the corresponding probes 41 ₁ to 4 ₁ of the probe assembly 4.
It is incident on 1 ₂₀ .

The measuring laser beam light is emitted from the probes 41 ₁ to 4 _1.
It is reflected by the 1 ₂₀ each of the bottom surface of the mirror (not shown), as reflected return light via the condenser lens 5 and the 1/8 wavelength plate 6, returns to the polarization beam splitter 7. At this time, since the measurement laser beam light and the reflected return light are transmitted through the ⅛ wavelength plate 6 to be provided with an optical bias of ⅛ wavelength, respectively, the probes 41 _{1 to} 41 ₂₀ are elliptically polarized. While the measurement laser beam light is incident, the circularly polarized reflected return light is incident from the opposite direction to the polarization beam splitter 7 to which the linearly polarized measurement laser beam light is incident. Therefore, the polarization beam splitter 7 reflects about half the amount of the circularly polarized reflected return light,
The light is incident on each of the ₂₀ photosensors 10 ₁ to 10 ₂₀ .

Here, 20 probes 41 ₁ to
When there is a change in the refractive index due to the electric field from the unit electrodes 21 adjacent to each other at 41 ₂₀ , the polarization state of the reflected return light becomes different from the circularly polarized light in response to this, and therefore the reflected return light is reflected by the polarization beam splitter 7. Since the amount of light is different, the amount of light corresponding to the electric field applied to each of the ₂₀ probes 41 _{1 to} 41 ₂₀ is input to the ₂₀ optical sensors 10 ₁ to 10 ₂₀ . Therefore, the LCD panel 2
Simultaneous potential measurement of the upper 20 unit electrodes 21 becomes possible.

[0025] In FIG. 1, the light source driver 32 continuously emits 20 of the semiconductor laser 91 ₁ to 91 ₂₀ (CW emission)
The measuring device 33 is a circuit that makes 20 optical sensors 10
_1-10 on the basis of the output of _20, and requests the data corresponding to the electric field applied to the unit electrodes 21 of the LCD panel 2, 20 in response to the optical sensor 10 ₁ to 10 ₂₀ to 20 measurement channels or It has a measuring unit. The measurement operation will be described in detail later.

The CPU 34 is composed of, for example, a personal computer, which moves the LCD panel 2 by driving the XY stage 1, pulse-drives the LCD panel 2 with the pulse-driving signal source 31, and measures the instrument 33. It has a role of synchronizing with the measurement operation, and based on the data given from the measuring device 33, it is determined which of the many unit electrodes 21 of the LCD panel 2 is malfunctioning. Note that these control and measurement operations will also be described later.

[0027] In this embodiment, as shown in FIG. 2, the 20 probe 41 _{1-41 20} has a probe assembly 4 arranged in a staggered manner, each of the probes 41 ₁ to 41 ₂₀ to 10 consecutive Since the area of each unit electrode 21 is covered, as a result, 20 × 10 = 200 unit electrodes 21 are formed.
The area can be covered with one probe assembly 4. That is, in each of the 20 units, the measurement laser beam light is deflected by the deflector 8 in the array direction (or in the direction oblique to the array direction). The region of the unit electrode 21 can be irradiated with the measurement laser beam light.

In addition, the unit electrode 21 is turned on (voltage applied) at least once within the time during which the region of the unit electrode 21 is irradiated with the measurement laser beam light.
By driving the LCD panel 2 with the pulse drive signal source 31, information about the potential of the unit electrode 21 is optically obtained.

Further, when one deflection of the measurement laser beam light by the deflector 8 including a galvanometer mirror and an acoustic light deflector is completed, the probe assembly 4 is placed on the array electrode of the next line on the LCD panel 2. To be located at X-
The Y stage 1 is driven. After that, the deflecting device 8 starts the next deflection operation of the measurement laser beam light, and the potential can be measured in the same manner.

When the above measurement is repeated and the measurement operation from the upper end to the lower end in the Y direction is completed, the XY stage 1 is driven in the X direction and moved by the length of the probe assembly 4 in the Y direction. To move to (see FIG. 2). Hereinafter, by repeating this, the entire surface of the electrode area 20 on the LCD panel 2 having a two-dimensional spread is measured.

Next, the configuration and operation of the above-described embodiment will be described in detail with a model simplified by reducing the number of units.

FIG. 3 is a perspective view conceptually showing an example in which the inspection apparatus is composed of six inspection units. As shown,
Each of the six inspection units includes an optical unit including a polarization beam splitter 7 and a deflector 8 (both not shown), a condenser lens 5 _{1 to} 5 ₆ and an optical sensor 10 ₁ to 10 attached to the optical unit. ₆ and semiconductor lasers 91 _{1 to} 91 ₆
It is composed of In addition, the six probes 41 _{1 to} 41
_{6 is} also provided corresponding to these. The bottom surfaces of the probes 41 _{1 to} 41 ₆ are sufficiently close to the unit electrode 21 on the LCD panel 2, and the lines of electric force due to the potential of the unit electrode 21 reach the probe 41 and change its refractive index. Is being done.

As is clear from FIG. 3, the lines of the unit electrodes 21 corresponding to the _three probes 41 _{1 to} 41 ₃ in the upper row (arranged lines in the array direction) are the three probes 41 _{4 to} 41 in the lower row. ₆ is a line above the line of the corresponding unit electrode 21 (+ Y direction). This can be realized by arranging the probes 41 _{1 to} 41 ₆ in a staggered pattern and making the arrangement pitch of the probes 41 in the upper row and the lower row the same as the arrangement pitch of the unit electrodes 21 in the direction orthogonal to the array direction.

By arranging the probes 41 _{1 to} 41 ₆ in a zigzag manner in this manner, the condenser lens 5 ₁ as shown in FIG.
˜5 ₆ , photosensors 10 ₁ to 10 ₆ , semiconductor laser 91 ₁
Etc. In addition to the optical unit to 91 ₆ are also arranged in a zigzag pattern. The optical unit and the condenser lenses 5 _{1 to} 5 ₆ can be shared as shown in FIG.

FIG. 4 is a perspective view showing the XY stage 1 and the probe assembly 4. XY stage 1 has LC on top
An upper plate 11 on which the D panel 2 is placed, a Y drive plate 12 that moves the upper plate 11 in the Y direction along a guide, and a Y drive plate 1.
X drive plate 13 for moving 2 in the X direction along the guide. Y drive motor 14 is attached to Y drive plate 12, and X drive motor 15 is attached to X drive plate 13.

The device of FIG. 4 operates as follows. First, the LCD panel 2 is placed on the upper plate 11, the probe assembly 4 is lowered together with the optical system, and the bottom surface of the probe assembly 4 and the top surface of the LCD panel 2 are sufficiently close to each other. When starting the measurement, the probe assembly 4 is attached to the LCD panel 2
The display area 20 is located at the upper left end (-X, + Y direction).

When the measurement is started, as described above, the six measuring laser beam lights are incident on the corresponding probes 41 _{1 to} 41 ₆ by the deflector 8 while being deflected in the X direction. At this time, the Y drive motor 14 gradually moves the upper plate 11 in the Y direction.

When the deflection of the measurement laser beam light by the deflector 8 makes one reciprocation, the probes 41 _{1 to} 41 ₆ respectively move to the next line (adjacent array in the Y direction) of the array electrode composed of the unit electrodes 21 in the display area 20. Electrode) has moved to the top. Therefore, in the deflection of the deflector 8 in the next cycle, the measurement laser beam light is incident on the area of the line next to the previous line.

When the above operation is repeated by the number of unit electrodes 21 in the Y direction of the LCD panel 2 (more precisely, the number of unit electrodes 21 in the Y direction plus 1), one voltage measurement in the Y direction is performed. finish. As a result, the X drive motor 15 causes the Y drive plate 12 to move stepwise in the -X direction, and this time the deflection of the measurement laser beam light by the deflector 8 is repeated while starting to move in the -Y direction.

The movement control by the XY stage 1 described above will be specifically described. Here, color VGA (640 dots × 480 dots × 3 colors = 921,600 pixels) LC
Consider that the electrical characteristics of the D panel are measured in 1 minute per sheet. The effective length of the probe assembly 4 in the array direction is 20 mm, the effective length of one probe 41 in the array direction is 1 mm, and each probe 41 has ten unit electrodes 21 (pitch is 300 μm × 100 μm. The size is set as large as possible.) With this setting, 200 pixels can be measured in one scan, and therefore 640 × 3/200 = 9.6, that is, 1 for measuring the entire LCD panel 2.
It is necessary to move the LCD panel 2 only 0 times.

At this time, the distance of one movement in the Y direction from the upper end to the lower end of the LCD panel 2 is 300 μm × 480 = 1.
Since it is 44 mm, the total is 144 mm × 10 = 1,4
It is necessary to move by 40 mm. Then this is 1
In order to perform in minutes, the moving speed of the XY stage 1 in the Y direction is 24 mm / sec, but this is sufficiently possible with the mechanical XY stage 1.

That is, in this embodiment, the XY stage 1 is used.
Does not move stepwise in the Y direction (orthogonal to the array) but moves at a constant speed, so that it is possible to measure the potential of an extremely large number of pixels (unit electrodes) in a short time. If step movement is required,
The acceleration at the moment of starting and stopping the movement is extremely large, whereas the weight of the XY stage 1 and the LCD panel 2 is considerably large, and thus such movement becomes very difficult.

FIG. 5 is a perspective view showing the structure of each inspection unit, particularly the structure of the optical system. As shown in the figure, the measurement laser beam light output from the semiconductor laser 91 is collimated by the collimator lens 101 and is incident on the deflector 8. The deflector 8 reciprocates and deflects the measurement laser beam light in the array direction (or oblique direction) at a substantially constant angular velocity, and the deflected measurement laser beam light is incident on the polarization beam splitter 7 via the lens 102.

By passing through the polarization beam splitter 7, the measurement laser beam light is made into a linearly polarized beam light, and an 1/8 wavelength optical bias is given by the 1/8 wavelength plate 6. That is, the measurement laser beam light is elliptically polarized and is incident on the probe 41 via the condenser lens 5. Although the reflected light from the bottom surface of the probe 41, that is, the reflected return light of the measurement laser beam light is approximately elliptically polarized light,
The polarization state is different from the elliptical polarization depending on the change in the refractive index of the probe 41 itself due to the electric field applied to the probe 41.

This reflected return light is collected by the condenser lenses 5 and 1 /
The light is again incident on the polarization beam splitter 7 via the eight-wave plate 6 and the optical path is converted to a right angle direction. At this time, 1/8
Since the 1/8 wavelength optical bias is given again by passing through the wave plate 6, the reflected return light that has entered the polarization beam splitter 7 becomes approximately circularly polarized light, and the polarization state changes by the change in the refractive index of the probe 41. There is.

Therefore, the amount of light whose optical path is changed by the polarization beam splitter 7 is 50% if it is circularly polarized light, but if the polarization state is deviated from circularly polarized light, the amount of light is passed through the lens 103 accordingly. The amount of reflected return light incident on the optical sensor 10 is different. Therefore, the electric field applied to the probe 41 can be obtained from the optical detection level of the optical sensor 10.

FIG. 6 is a schematic perspective view showing how the deflected measurement laser beam light enters and is reflected by the probe 41. In the illustrated example, the probe 41 is 8
The area of each unit electrode 21 is covered, and the measurement laser beam light is gradually deflected in the array direction from one end (lower left side in FIG. 6) to the other end (upper right side in FIG. 6). To scan the probe 41. Therefore, during the time when the measurement laser beam light is incident on the probe 41 in the region corresponding to each of the eight unit electrodes 21, the polarization state of the reflected return light depends on the potential of each of the eight unit electrodes 21. Contains information.

Next, some examples of the measuring method according to the present invention will be described with reference to FIGS. 7 to 11.
In order to simplify the explanation, one probe 41 has four
It is assumed that the probe assembly 4 has six probes 41 that respectively cover the regions of the unit electrodes 21a to 21d and cover the first to sixth areas.

FIG. 7 shows the probe 4 for measuring laser beam light.
1 shows a parallel scanning method in which the light is deflected in the direction parallel to the longitudinal direction of 1 (array direction). As shown in FIG. 7A, when the spot of the measurement laser beam light gradually moves from the left side to the right side of the probe 41 as indicated by the solid arrow, and then gradually returns from the right side to the left side as indicated by the dotted arrow, The unit electrodes 21a to 21d of the LCD panel 2 are measured at different potentials from the upper side to the lower side as shown in FIG. 7B. This is because the XY stage 1 moves L while the measuring laser beam light is scanned by the deflector 8.
This is because the CD panel 2 has been moved. Note that the measurement is performed here when the solid arrow moves, and not when the dotted arrow returns.

FIGS. 7 (c) to 7 (f) are exploded views showing how the region where the measurement laser beam light is incident moves from the unit electrode 21a on the left side to the unit electrode 21d on the right side.
The unit electrode 21a on the left side is irradiated with the measurement laser beam light in an area about 1/4 from the upper end, but the unit electrode 21a on the right side is
In d, the measurement laser beam light is applied to a region of about 1/4 from the lower end. When the light spot is returned by the dotted arrow, the measurement laser beam light is irradiated near the boundary of each unit electrode.

FIG. 8 shows that the area of the array electrode composed of 4 × 6 = 24 unit electrodes 21 is divided into six measurement laser beams for each of the first to sixth areas by the parallel scanning method of FIG. It shows a state of being scanned by light. In FIG. 8, it is assumed that the first to sixth areas are each covered with _six probes 41 _{1 to} 41 ₆ . Also,
The black circle indicates the area where the measurement laser beam is incident and the potential is being measured, the white circle indicates the area where the measurement laser beam has already been incident and the measurement has been completed, and the cross indicates the measurement laser beam has been incident but the potential has been measured. Indicates an area that does not exist.

As shown in FIG. 8A, in the first line of the second, fourth, sixth area and the second line of the first, third, fifth area, the measurement starts from the unit electrode 21 on the left side. The position is about 1/4 from the upper end of each unit electrode 21. Then, as shown in FIG. 8B, the unit electrode 2 on the right side of each area
The measurement proceeds up to 1, but the position at this time is at each unit electrode 21.
It has moved from the lower end to about 1/4. That is, only half of the vertical arrangement pitch of the unit electrodes 21 is used for the XY stage 1.
When is moved, the one-way deflection by the deflector 8 is completed.

When the measurement of the four unit electrodes 21 is completed in this way, the measurement laser beam light is deflected in the return direction (see FIG. 8C) and passes through the boundary region between the two unit electrodes, Finally, the area of the unit electrode 21 on the left side of the next line is irradiated with the measurement laser beam light. At this time, the measurement position is about 1/4 from the upper end of the left unit electrode 21.
That is, the time required for the polarization beam splitter 7 to deflect the measurement laser beam light for one cycle is equal to the time required for the LCD panel 2 to move by the arrangement pitch of the array electrodes in the orthogonal direction. Below, FIG. 8 (d)
The same scan is repeated as in.

To explain the above parallel scan method more specifically, first, the pitch of the unit electrodes 21 is 300 μm in the vertical direction,
Assuming that the width of 100 μm and one probe 41 covers ten unit electrodes 21, the length of the probe 41 may be 1000 μm + α (α is the extra length of the probe 41).

When the 1/4 position from the upper end of the left end unit electrode 21 is on the measurement line, the measurement laser beam light is irradiated to this and it is deflected to the right unit electrode 21. When the tenth rightmost unit electrode 21 is irradiated with the measurement laser beam, the position is set to be ¼ from the lower end of the unit electrode 21. That is, the measurement laser beam light is 10 × 100 μ from left to right.
While scanning m = 1000 μm, the XY stage 1
Is controlled to move in the Y direction by 300 μm / 2 = 150 μm.

FIG. 9 shows a probe 41 for measuring laser beam light.
2 shows an oblique scanning method in which the light is deflected obliquely with respect to the longitudinal direction. The scan in this case is realized by inclining the deflector 8 obliquely with respect to the probe 41. Figure 9
As shown in FIG. 9A, when the measurement laser beam light is scanned in the upper right direction as shown by the solid line and returned to the lower left direction as shown by the dotted line, the unit electrodes 21a to 21 are made as shown in FIG. 9B.
For d, the potential is measured at almost the same position. This is because the XY stage 1 moves the LCD panel 2 during the scanning of the measurement laser beam light.

9C to 9F show the left unit electrode 2
It shows that the irradiation position of the measurement laser beam light sequentially changes from 1a to the right unit electrode 21d. If such an oblique scan is adopted, six probes 41 ₁ to 4
The first to the potential measurement of the sixth area of the unit electrodes 21 by 1 ₆ is as shown in FIG. 10 (a) ~ (d) .

FIGS. 10A to 10D are shown in FIGS.
The difference from (d) is that the potential measurement by the measurement laser beam light is always performed on the central portion of the unit electrode 21. Therefore, this oblique scan method is suitable for potential measurement when the unit electrode 21 is not long in the direction orthogonal to the array direction. 11A to 11E show
This case is shown. Each unit electrode has a substantially square shape.

More specifically, the oblique scanning method will be described. A large number of unit electrodes 21 arranged with a pitch of 300 μm and a width of 100 μm are measured while one probe 41 covers ten unit electrodes 21. Sometimes X-
While the Y stage 1 moves in the vertical direction (Y direction) by 300 μm / 2 = 150 μm, the measurement laser beam light becomes 100 μm × 10 = 1000 μm in the horizontal direction (X direction) and 150 μm in the vertical direction (Y direction). Scan diagonally. By doing so, the measurement laser beam light is incident on the same height (Y direction) position of the unit electrode 21, and when returning, it becomes the same height position of the unit electrode 21 of the next line.

Next, the method of measuring the potential of the unit electrode in the embodiment will be described, particularly for real-time measurement (FIG. 13) and synchronous measurement (FIG. 14).

FIG. 12 is a configuration diagram of an inspection unit for explaining these measuring methods, and one inspection unit is extracted from FIG. As shown in the figure, the measurement laser beam light from the semiconductor laser 91 is deflected by the deflector 8 so as to reciprocate, is linearly polarized by the polarization beam splitter 7, and is then elliptically polarized by the ⅛ wave plate 6, for example. Is scanned into. At this time, the potential of the unit electrode 21 on the LCD panel 2 is changed in a pulsed manner by the pulse drive signal source 31, and the reflected return light having a change in polarization state due to this is subjected to optical path conversion by the polarization beam splitter 7. It is incident on the optical sensor 10.

The number of pixels of the color VGA panel is extremely large, and in the above example, the number of all pixels is 921,600, and since measurement is not performed in the returning path of the scan of the measurement laser beam light, measurement per pixel is performed. Time is 60
sec × 20 / (921,600 pixels × 2 round trips) =
It is necessary to perform it in 0.65 msec. As will be described later with reference to FIG. 13, if the measurement of each pixel is measured in real time, the frequency of the electric signal for driving the panel is 1 /
It is sufficient if 0.65 msec = 1.54 kHz or more.
Further, as will be described later with reference to FIG. 14, when performing synchronous measurement using a lock-in amplifier or the like, the panel may be driven at a frequency that is several times that frequency or higher.

When inspecting an LCD panel or the like, it is not necessary to observe the detailed waveform of the voltage to be measured, and it is sufficient to know only the voltage value. Further, what is to be detected is whether or not there is a defective pixel, and even if the absolute value of the voltage of each pixel is not known, it is sufficient to know the difference from a non-defective pixel. Considering such a situation, the signal detection method can be considerably simplified as shown in FIG. 13 or FIG. 14 below.

FIG. 13 is a waveform diagram when real-time measurement is performed by the system of FIG. Here, the pulse drive signal source 31 and the measuring instrument 33 are operating in synchronization,
Here, for simplification, it is assumed that the unit electrode 21 of the LCD panel 2 is pulse-driven four times within the time when the measurement laser beam light is incident on the area of one unit electrode 21.

FIG. 13A shows a drive signal waveform to the unit electrode 21 of the LCD panel 2, and four pulses are applied to each of the pixels A, B and C. Note that this is 4 × 1.54 kHz = 6.16 kHz under the above-mentioned conditions.
Becomes Then, a pulsed electric field is similarly applied to the region of the probe 41 corresponding to each unit electrode 21, so that the photodetection output signal detected by the photosensor 10 is as shown in FIG. 13B. Change.

When the output of the optical sensor 10 is passed through a bandpass filter (high frequency cut filter), the high frequency noise is cut and the DC component is removed (DC correction), and the waveform is as shown in FIG. 13C. Become. The band-pass filter is a narrow-band filter whose center frequency is the frequency of the drive signal from the pulse drive signal source 31. As a result, the DC bias and noise are removed as described above.

When the maximum value and the minimum value in each cycle of pulse driving are sampled for this output, the waveform becomes as shown in FIG. 13 (d). Therefore, when the difference between the maximum value and the minimum value in the pulse drive of the third period in each pixel A, B, C is taken out as an output value, the final output is shown in FIG.
become that way. In this way, it is understood that the proper potential is applied to the pixels A and C, but the potential is insufficient for the pixel B, and the unit electrode 21 malfunctions.

FIG. 14 is a waveform diagram when synchronization detection is performed in the system of FIG. In this example, the LCD panel 2
The reference signal from the drive signal source 31 of the
Based on the reference signal, the measuring device 33 including a lock-in amplifier detects the synchronization. In the case of the synchronous detector, the equivalent frequency bandwidth can be made narrower than in the above real-time measurement method, and a better S / N can be obtained.

However, since it takes time to stabilize the output as compared with the real-time measurement method, a drive signal with many cycles is required as shown in FIG. 14 (a). The output signal from the photodetector 10 is equivalent to the real-time method,
The output of the sync detector changes slowly as shown in FIG. This output is peak-held, and the timing for holding it is when the output of the synchronization detector shown in FIG. 14 (c) becomes constant. FIG. 14D shows the state of peak hold in this way. The final output in FIG. 14E is the held output value, and the pixel B is determined to be defective. At the time of panel inspection, it is sufficient to make a judgment based only on this output value.

In the above embodiment, the AC drive signal is supplied from the pulse drive signal source 31 to the LCD panel 2.
Depending on the electrode configuration of the CD panel 2, there are some that can only apply a DC voltage. FIG. 15 shows a measuring method for solving such a problem, that is, a resistivity modulation method.

FIG. 15 shows an example in which the voltage at the device under test (unit electrode 21 of LCD panel 2) is a DC voltage. EO that constitutes the probe assembly 4
As the probe 41, a crystal having both the electro-optical effect and the photoconductive effect, for example, ZnTe is used. As the laser light source 91 for the probe, C having a wavelength of 780 nm is used.
W semiconductor laser diode is used, and in addition, as the second light source (chopping light source) 105, the emission wavelength 514.
A 5 nm Ar ⁺ laser light source is used.

A dichroic mirror 104 is placed on the optical path between the condenser lens 5 and the ⅛ wavelength plate 6, which transmits the measurement laser beam light from the laser light source 91 for the probe and Ar ^+. Laser light from the laser light source 105 (laser light chopped by the chopper 106) is reflected. A DC voltage is applied from the DC power supply 38 to each unit electrode of the LCD panel 2. And
The operation of the chopper 106 pulse driving means and the operation of the lock-in amplifier 33 are controlled in synchronization with each other.

Here, when the light from the Ar ⁺ laser light source 105 is absorbed in the crystal (probe 41), an electric charge is generated in the EO crystal due to the photoconductive (photocon) effect,
As a result, the resistance of the crystal is lowered and the voltage applied to the electrodes is less likely to be applied to the EO probe 41, and the electro-optical effect is substantially eliminated. Therefore, when the light from the Ar ⁺ laser is ON / OFF modulated (pulse modulated) by the chopper 106 and incident on the EO probe 41, the EO effect of ZnTe can be turned OFF / ON in synchronization therewith. . This is equivalent to applying the modulation to the voltage to be measured as shown in FIG. 12, so that even if the DC voltage applied to the LCD panel 2 can be measured.

[0074]

As described above, according to the array electrode substrate inspection apparatus of the present invention, since the plurality of electro-optical probes are arranged in a staggered manner in the probe assembly, by using a plurality of small electro-optical probes, Since this is equivalent to configuring a long electro-optic probe, non-contact simultaneous measurement of the potentials of a large number of unit electrodes becomes possible. That is, since the measurement beam light is incident on each electro-optical probe and each reflected return light is detected by the photo-detecting means, the potentials of the unit electrodes corresponding to the number of electro-optical probes can be simultaneously measured.

Since the deflection of the measurement beam light in the array direction or in this oblique direction is synchronized with the relative movement of the array electrode and the probe assembly in the direction orthogonal to the array direction, the measurement of the array electrode on a certain line is completed. Then, the measurement of the array electrode of the next line can be started, and as a result, it becomes possible to continuously measure the potential and measure the potentials of a large number of pixels in a short time.

Further, by supplying the pulse drive signal to the array electrode substrate, not only the electric potential of the unit electrode can be accurately measured while the measurement light beam is continuous light, but also the array electrode substrate is driven by direct current. Also, the potential of the unit electrode can be measured well with S / N.

[0077]

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an array electrode substrate inspection apparatus according to an embodiment.

FIG. 2 is a diagram showing a relationship between a liquid crystal display panel and an EO probe.

FIG. 3 is a perspective view schematically showing the overall configuration.

FIG. 4 is a perspective view showing a relationship between an XY stage and an EO probe.

FIG. 5 is a perspective view showing an optical system of one inspection unit.

FIG. 6 is a perspective view showing the relationship between the EO probe and the measurement laser beam light.

FIG. 7 is a diagram showing a parallel scan method.

FIG. 8 is a diagram showing a parallel scan method.

FIG. 9 is a diagram showing an oblique scanning method.

FIG. 10 is a diagram showing an oblique scanning method.

FIG. 11 is a diagram showing an oblique scanning method.

FIG. 12 is a diagram of one inspection unit for explaining the measuring method.

13 is a waveform diagram illustrating real-time measurement in the system of FIG.

14 is a waveform diagram showing synchronous measurement in the system of FIG.

FIG. 15 is a configuration diagram of an inspection unit to which measurement by a resistivity modulation method is applied.

FIG. 16 is a diagram of a monochrome display LCD panel.

FIG. 17 is a diagram of a color display LCD panel.

[Explanation of symbols]

1 ... XY stage, 2 ... LCD panel, 21 ... Unit electrode, 31 ... Pulse drive signal source, 33 ... Measuring instrument, 4 ... Probe assembly, 41 ... Probe, 5 ... Condensing lens, 6 ... 1
/ 8 wavelength plate, 7 ... polarizing beam splitter, 8 ... deflector,
9 ... Laser light source, 91 ... Semiconductor laser, 10 ... Optical sensor.

Claims (5)

(57) [Claims] 1. An array electrode, in which a plurality of unit electrodes whose potentials are to be measured are arrayed in one direction, is arrayed at a predetermined array interval in a direction orthogonal to the array direction,
In an inspection device for inspecting an array electrode substrate in which the unit electrodes are two-dimensionally arranged, a plurality of electro-optical probes each having a length in the array direction including a plurality of the unit electrodes are arranged at a predetermined pitch. A probe assembly having two probe arrays, wherein the electro-optical probe of each of the one probe array and the electro-optical probe of each of the other probe array are arranged in a staggered pattern; A probe light source that outputs a plurality of measurement beam lights corresponding to each of the plurality of electro-optic probes of the probe assembly, and a plurality of measurement beam lights from the probe light source, respectively, in the array direction or in the oblique direction. Deflecting means for repeatedly deflecting the plurality of measurement beam lights deflected by the deflecting means to the plurality of electro-optical devices. An optical system that is incident on each of the probes, an optical path converting unit that converts the optical paths of a plurality of reflected return lights of the plurality of measurement beam lights that are incident on the plurality of electro-optical probes, and an optical path by the optical path converting unit. Light detection means for detecting the converted plurality of reflected return lights for each of the plurality of electro-optical probes; the probe assembly and the array electrode in synchronization with a repetition cycle of deflection of the measurement beam light by the deflection means. An array electrode substrate inspection apparatus, comprising: a moving unit that relatively moves the substrate in a direction orthogonal to the array direction by an arrangement interval of the array electrodes. 2. The probe light source has a plurality of semiconductor lasers that respectively output the plurality of measurement beam lights, and the light detection unit has a plurality of photosensors that respectively detect the plurality of reflected return lights. 1. The array electrode substrate inspection device according to 1. 3. The moving means has a stage on which the array electrode substrate is placed and which moves the array electrode substrate in a direction orthogonal to the array direction.
The array electrode substrate inspection device described. 4. The unit electrode is measured a plurality of times within the time when the measurement beam light is deflected by the deflecting means and is incident on the electro-optic probe in a region corresponding to one unit electrode. 2. The array electrode substrate inspection device according to claim 1, further comprising a pulse drive source that supplies a pulse drive signal having a power potential to the array electrode substrate. 5. The electro-optical probe is made of a material that produces a photoconductive effect by light having a wavelength shorter than that of the measurement beam light, and supplies a DC drive signal to the array substrate, the DC drive signal having a potential to measure the unit electrode. A direct current drive source, a light source for irradiating the plurality of electro-optic probes with the light of the short wavelength, and the electro-optic of a region corresponding to one of the unit electrodes by the measurement beam light being deflected by the deflection means. Turning on the electro-optical probe with the short wavelength light so that the electro-optical probe is flashed with the short wavelength light while being incident on the probe.
The array electrode substrate inspection device according to claim 1, further comprising a chopping means for turning off.